Stephen Seiler

Quantifying training intensity distribution in elite endurance athletes: is there evidence for an “optimal” distribution?

This study was designed to quantify the daily distribution of training intensity in a group of well‐trained junior cross‐country skiers and compare the results of three different methods of training intensity quantification. Eleven male athletes performed treadmill tests to exhaustion to determine heart rate and VO2 corresponding to ventilatory thresholds (VT1, VT2), maximal oxygen consumption (VO2max), and maximal heart rate. VT1 and VT2 were used to delineate three intensity zones. During the same time period, all training sessions (N=384, 37 strength training, 347 endurance) performed over 32 consecutive days were quantified using continuous heart rate registration and session Rating of Perceived Exertion (RPE). In addition, a subset of 60 consecutive training sessions was quantified using blood lactate measurements. Intensity distribution across endurance training sessions (n=318) was similar when based on heart rate analysis (75±3%, zone 1; 8±3%, zone 2; 17±4%, zone 3) or session RPE (76±4%, zone 1; 6±5%, zone 2; 18±7%, zone 3). Similarly, from measurements of 60 consecutive sessions, 71% were performed with ≤2.0 mM blood lactate, 7% between 2 and 4 mM, and 22% with over 4 mM (mean=9.5±2.8 mM). In this group of nationally competitive junior skiers, training was organized after a polarized pattern, with most sessions performed clearly below (about 75%) or with substantial periods above (15–20%) the lactate accommodation zone, which is bounded by VT1 and VT2. The pattern quantified here is similar to that reported in observational studies of elite endurance athletes across several sports. It appears that elite endurance athletes train surprisingly little at the lactate threshold intensity.

Impact of training intensity distribution on performance in endurance athletes.

The purpose of this study was to compare the effect of 2 training programs differing in the relative contribution of training volume, clearly below vs. within the lactate threshold/maximal lactate steady state region on performance in endurance runners. Twelve subelite endurance runners (who are specialists in track events, mostly the 5,000-m race usually held during spring-summer months and who also participate in cross-country races [9–12 km] during fall and winter months) were randomly assigned to a training program emphasizing low-intensity (subthreshold) (Z1) or moderately high-intensity (between thresholds) (Z2) training intensities. At the start of the study, the subjects performed a maximal exercise test to determine ventilatory (VT) and respiratory compensation thresholds (RCT), which allowed training to be controlled based on heart rate during each training session over a 5-month training period. Subjects performed a simulated 10.4-km cross-country race before and after the training period. Training was quantified based on the cumulative time spent in 3 intensity zones: zone 1 (low intensity; VT), zone 2 (moderate intensity; between VT and RCT), and zone 3 (high intensity; RCT). The contribution of total training time spent in zones 1 and 2 was controlled to have relatively more low-intensity training in Z1 (80.5 ± 1.8% and 11.8 ± 2.0%, respectively) than in Z2 (66.8 ± 1.1% and 24.7 ± 1.5%, respectively), whereas the contribution of high-intensity (zone 3) training was similar (8.3 ± 0.7% [Z1] and 8.5 ± 1.0% [Z2]). The magnitude of the improvement in running performance was significantly greater (p = 0.03) in Z1 (−157 ± 13 seconds) than in Z2 (−121.5 ± 7.1 seconds). These results provide experimental evidence supporting the value of a relatively large percentage of low-intensity training over a long period (−5 months), provided that the contribution of high-intensity training remains sufficient.

Effect of core stability training on throwing velocity in female handball players.

Saeterbakken, AH, van den Tillaar, R, and Seiler, S. Effect of core stability training on throwing velocity in female handball players. J Strength Cond Res 25(3): 712-718, 2011-The purpose was to study the effect of a sling exercise training (SET)-based core stability program on maximal throwing velocity among female handball players. Twenty-four female high-school handball players (16.6 ± 0.3 years, 63 ± 6 kg, and 169 ± 7 cm) participated and were initially divided into a SET training group (n = 14) and a control group (CON, n = 10). Both groups performed their regular handball training for 6 weeks. In addition, twice a week, the SET group performed a progressive core stability-training program consisting of 6 unstable closed kinetic chain exercises. Maximal throwing velocity was measured before and after the training period using photocells. Maximal throwing velocity significantly increased 4.9% from 17.9 ± 0.5 to 18.8 ± 0.4 m·s−1 in the SET group after the training period (p < 0.01), but was unchanged in the control group (17.1 ± 0.4 vs. 16.9 ± 0.4 m·s−1). These results suggest that core stability training using unstable, closed kinetic chain movements can significantly improve maximal throwing velocity. A stronger and more stable lumbopelvic-hip complex may contribute to higher rotational velocity in multisegmental movements. Strength coaches can incorporate exercises exposing the joints for destabilization force during training in closed kinetic chain exercises. This may encourage an effective neuromuscular pattern and increase force production and can improve a highly specific performance task such as throwing.

Effect of work duration on physiological and rating scale of perceived exertion responses during self-paced interval training

This study compared running velocity, physiological responses, and perceived exertion during self‐paced interval training bouts differing only in work bout duration. Twelve well‐trained runners (nine males, three females, 28±5 years, VO2 max 65±6 mL min−1 kg−1) performed preliminary testing followed by four “high‐intensity” interval sessions (Latin squares, 1 session week−1 over 4 weeks) consisting of 24×1, 12×2, 6×4, or 4×6‐min running bouts with a 1:1 work‐to‐rest interval (total session duration 48 min). The average running velocity decreased (93%, 88%, 86%, 84% vVO2 max, P<0.01) with increasing work duration. Peak VO2 averaged about 92±4% of VO2 max for 2‐, 4‐, and 6‐min intervals compared with only 82±5% for 1‐min bouts (P<0.001). Six of 12 athletes achieved their highest average VO2 and heart rate during 4‐min intervals. The average RPEpeak (rating scale of perceived exertion) was ∼17±1 for all four interval sessions. RPE increased by 2–4 U during an interval training session. The mean lactate concentration was similar across sessions (4.3±1.1–4.6±1.5 mmol L−1). Under self‐paced conditions, well‐trained runners perform “high‐intensity” intervals at an RPE of ∼17, independent of interval duration. The optimal interval duration for eliciting a high physiological load is 3–5 min under these training conditions. Increases in RPE during an interval bout are not associated with increasing blood lactate concentration.

Adaptations to aerobic interval training: interactive effects of exercise intensity and total work duration.

To compare the effects of three 7‐week interval training programs varying in work period duration but matched for effort in trained recreational cyclists. Thirty‐five cyclists (29 male, 6 female, VO2peak 52 ± 6 mL kg/min) were randomized to four training groups with equivalent training the previous 2 months (∼6 h/wk, ∼1.5 int. session/wk). Low only (n=8) trained 4–6 sessions/wk at a low‐intensity. Three groups (n=9 each) trained 2 sessions/wk × 7 wk: 4 × 4 min, 4 × 8 min, or 4 × 16 min, plus 2–3 weekly low‐intensity bouts. Interval sessions were prescribed at the maximal tolerable intensity. Interval training was performed at 88 ± 2, 90 ± 2, and 94 ± 2% of HRpeak and 4.9, 9.6, and 13.2 mmol/L blood lactate in 4 × 16, 4 × 8, and 4 × 4 min groups, respectively (both P<0.001). 4 × 8min training induced greater overall gains in VO2peak, power@VO2peak, and power@4 mM bLa‐ (Mean ± 95%CI): 11.4 (8.0–14.9), vs 4.2 (0.4–8.0), 5.6 (2.1–9.1), and 5.5% (2.0–9.0) in Low, 4 × 16, and 4 × 4 min groups, respectively (P<0.02 for 4 × 8 min vs all other groups). Interval training intensity and accumulated duration interact to influence the adaptive response. Accumulating 32 min of work at 90% HR max induces greater adaptive gains than accumulating 16 min of work at ∼95% HR max despite lower RPE.

Functional level during sub-acute rehabilitation after traumatic brain injury: Course and predictors of outcome

Objectives: To describe the functional level during sub-acute rehabilitation after moderate and severe traumatic brain injury (TBI) and to evaluate the impact of pre-injury and injury-related factors as predictors of early recovery. Material and methods: A prospective study of 55 patients with moderate (n = 21) and severe (n = 34) TBI who received specialized, inpatient rehabilitation. Functional level was assessed by the FIM. Possible predictors were analysed in a regression model using FIM total score at discharge as outcome. Results: At discharge from sub-acute rehabilitation, on average 53 (±24) days post-injury, 57% of moderate TBI patients and 91% of severe TBI patients were still disabled with a FIM score < 126. The disability was mild (FIM 109–126) in 95% with moderate TBI and in 62% with severe TBI. The disability was severe (FIM < 72) in 24% with severe TBI. Only one patient did not improve. Predictors of functional level at discharge from rehabilitation were Glasgow Coma Scale (GCS) score at rehabilitation admission (B = 5.991), FIM total score at rehabilitation admission (B = 0.393), length of stay (LOS) in the rehabilitation unit (B = 0.264) and length of Post-Traumatic Amnesia (PTA) (B = −0.120). Together, these predictors explained 86% of variance of FIM total scores at discharge. Conclusion: Less than half of moderate TBI patients reached a normal functional level at discharge from sub-acute rehabilitation. A short PTA period, a high GCS score and FIM score at admission to rehabilitation and a longer stay in the rehabilitation unit were positive predictors of functional level at discharge.

The role and development of sprinting speed in soccer

The overall objective of this review was to investigate the role and development of sprinting speed in soccer. Time-motion analyses show that short sprints occur frequently during soccer games. Straight sprinting is the most frequent action before goals, both for the scoring and assisting player. Straight-line sprinting velocity (both acceleration and maximal sprinting speed), certain agility skills, and repeated-sprint ability are shown to distinguish groups from different performance levels. Professional players have become faster over time, indicating that sprinting skills are becoming more and more important in modern soccer. In research literature, the majority of soccer-related training interventions have provided positive effects on sprinting capabilities, leading to the assumption that all kinds of training can be performed with success. However, most successful intervention studies are time consuming and challenging to incorporate into the overall soccer training program. Even though the principle of specificity is clearly present, several questions remain regarding the optimal training methods within the larger context of the team-sport setting. Considering time-efficiency effects, soccer players may benefit more by performing sprint-training regimens similar to the progression model used in strength training and by world-leading athletics practitioners, compared with the majority of guidelines that traditionally have been presented in research literature.

The Road to Gold: Training and Peaking Characteristics in the Year Prior to a Gold Medal Endurance Performance

Purpose To describe training variations across the annual cycle in Olympic and World Champion endurance athletes, and determine whether these athletes used tapering strategies in line with recommendations in the literature. Methods Eleven elite XC skiers and biathletes (4 male; 28±1 yr, 85±5 mL. min−1. kg−1 , 7 female, 25±4 yr, 73±3 mL. min−1. kg−1 ) reported one year of day-to-day training leading up to the most successful competition of their career. Training data were divided into periodization and peaking phases and distributed into training forms, intensity zones and endurance activity forms. Results Athletes trained ∼800 h/500 sessions.year−1, including ∼500 h. year−1 of sport-specific training. Ninety-four percent of all training was executed as aerobic endurance training. Of this, ∼90% was low intensity training (LIT, below the first lactate threshold) and 10% high intensity training (HIT, above the first lactate threshold) by time. Categorically, 23% of training sessions were characterized as HIT with primary portions executed at or above the first lactate turn point. Training volume and specificity distribution conformed to a traditional periodization model, but absolute volume of HIT remained stable across phases. However, HIT training patterns tended to become more polarized in the competition phase. Training volume, frequency and intensity remained unchanged from pre-peaking to peaking period, but there was a 32±15% (P<.01) volume reduction from the preparation period to peaking phase. Conclusions The annual training data for these Olympic and World champion XC skiers and biathletes conforms to previously reported training patterns of elite endurance athletes. During the competition phase, training became more sport-specific, with 92% performed as XC skiing. However, they did not follow suggested tapering practice derived from short-term experimental studies. Only three out of 11 athletes took a rest day during the final 5 days prior to their most successful competition.

Labour analgesia: a randomised, controlled trial comparing intravenous remifentanil and epidural analgesia with ropivacaine and fentanyl.

Background and objective To compare the analgesic efficacy and side-effects of remifentanil intravenous patient-controlled analgesia (IVPCA) with walking epidural analgesia (EDA) during labour. Methods Thirty-nine parturient patients of mixed parity, with normal singleton pregnancies, were randomised to receive either remifentanil IVPCA (RA group) or EDA (EA group). The epidural solution contained ropivacaine 1 mg ml−1 and fentanyl 2 &mgr;g ml−1, and the initial dose was 10 ml h−1. Starting bolus of remifentanil was 0.15 &mgr;g kg−1, with subsequent steps of 0.15 &mgr;g kg−1. Lock-out time was 2 min, bolus infusion speed 2 ml min−1 (100 &mgr;g min−1) and there was no background infusion. Visual analogue scale was used for pain assessment. Maternal heart rate, blood pressure, oxygen saturation, respiratory rate, sedation, nausea/vomiting, itching, satisfaction and fetal/neonatal outcome were recorded. Results Thirty-seven parturient patients were analysed. Both treatments provided good analgesia, but with higher pain scores in the RA group. Pain reduction at the end of first and during second stage and maximum pain reduction were similar (RA/EA group): 27/26 (P = 0.920), 31/29 (P = 0.909) and 61/59 (P = 0.855), respectively. Maternal satisfaction was similar. Two parturients receiving remifentanil (6%) converted to epidural, one because of inadequate analgesia. Remifentanil produced more maternal sedation, desaturation (SaO2 < 92%) and need for supplemental oxygen. Neonatal outcome was reassuring. Highest mean total dose of remifentanil was 0.70 &mgr;g kg−1 (range 0.30–1.05). Conclusion Remifentanil IVPCA and epidural provided effective analgesia, with high maternal satisfaction scores and reassuring neonatal outcome. Remifentanil produced more maternal sedation and oxygen desaturation. Close monitoring is, therefore, mandatory.

THE DIFFERENCE IS IN THE START: IMPACT OF TIMING AND START PROCEDURE ON SPRINT RUNNING PERFORMANCE

Haugen, TA, Tønnessen, E, and Seiler, SK. The difference is in the start: impact of timing and start procedure on sprint running performance. J Strength Cond Res 26(2): 473–479, 2012—The difference is in the start: impact of timing and start procedure on sprint running performance. The purpose of this study was to compare different sprint start positions and to generate correction factors between popular timing triggering methods on 40-m/40-yd sprint time. Fourteen female athletes (17 ± 1 years), personal best 100 m: 13.26 (±0.68) seconds and 11 male athletes (20 ± 5 years), personal best 100 m: 11.58 (±0.74) seconds participated. They performed 2 series of 3 40-m sprints in randomized order: (a) start from the block, measured by means of Brower audio sensor (BAS) and Dartfish video timing (DVT), (b) 3-point start, measured by using hand release pod (HR) and DVT, and (c) standing start, triggered by both photocell across starting line (SFC), and foot release (FR) plus DVT. Video analysis was performed by 2 independent observers and averaged. Simultaneous measurements at national athletics competitions demonstrated that DVT and BAS were equivalent to Omega Timing within the limits of precision of video timing (±0.01 seconds). Hand and floor timer triggering showed small but significant biases compared with movement captured from video (0.02–0.04 seconds), presumably because of sensitivity of pressure thresholds. Coefficient of variation for test-retest timing using different starting positions ranged from 0.7 to 1.0%. Compared with block starts reacting to gunfire, HR, SFC, and FR starts yielded 0.17 ± 0.09, 0.27 ± 0.12, and 0.69 ± 0.11 second faster times, respectively, over 40 m (all p < 0.001) because of inclusion or exclusion of reaction time, plus momentum, and body position differences at trigger moment. Correction factors for the conversion of 40 m/40 yd and 40 yd/40 m were 0.92 and 1.08, respectively. The correction factors obtained from this study may facilitate more meaningful comparisons of published sprint performances.